Slurry type liquid treating apparatus



W. J. HUGHES SLURRY TYPE LIQUID TREATING APPARATUS March 23, 1954 3 Sheets-Sheet 1 Filed Feb. 26, 1951 INVEN TOR. J. Hu

Walter. yhes BY f AGENT March 23, 1954 w. J. HUGHES 2,673,181 SLURRY TYPE LIQUID TREATING APPARATUS Filed Feb. 26, 1951 Figure .3

. INVENTOR. Wdlter' J. Hughes AGENT March 23, 1954 w. J. HUGHES 2,673,181

SLURRY TYPE LIQUID TREATING AFJPARATUS Filed Feb. 26, 1951 5 Sheets-Sheet 3 Figure 5 INVENTOR. Walter J. Hughes Patented Mar. 23, 1954 2,673,181

UNITED? STATES PATENT? OFFICE? SLURRY TYPE LIQUID TREATING APPARATUS Walter-LHdghes', Tucson, Ariz., as'signor to In filco Incorporated, Tlicson,-Ariz., a, corporation of'Dlaivare Alm ication Februaryl26, 1951, Serial No; 212,761 14 Claims." (Cl. 210-16) This invention relates to an apparatus for the. sediment. In operation of slurry type treatingi continuous treatment of liquids -to remove subunits it has been found that very heavy para stances therefrom in solid'form, and .more' par? ticles formed in the treatment, or gritty material ticularly .to an apparatus for whatis'commonly in theliquid under treatment sometimes cannot I called slurry treatment of liquids. be held in suspension by. the liquid circulation. It is an object .of this invention to provide. and settle tothe floor cfthe tank from where 1 an improved slurry type liquid'treating apparatus. they must be removed. In accordance with the" Another object of the invention is to adapt present invention the liquid is dischargedifrom" apparatus ofthe slurrytype to the. handling the mixing. and reactionzone throughlrotatin'g of heavy precipitate or mixtures of precipitate conduits or arms extending radially across the. and gritty materials'which tend to settle to the tank, and the velocity of the liquid'returning' to'i'. bottom of the tank. the mixing and reaction chamber is utilizedifor Another object. is to provide in a slurry type sweeping the bottom of the tank. Th'einwardxi liquid treating apparatus uniform distribution of return flow to the mixing and reaction chamber the mixture of s1urry,,incomin'g liquid and chemiis confined to prevent disturbance of theiover cals discharged from themixingand reaction lying slurry blanket due..to its relativelyghigh" chamber over the entirecross sectional area of the velocity, and isdirected to' sweep anyjdeposits' surrounding portions of. thetanlgand a coninto a centrally.locatedsump;

trolled return flow to the mixing and reaction The invention will bemorexreadilyunderstoodt .1 chamber from the entire crosswsectional areaz by reference to the detailed description which. of the surrounding tank portions. follows and tothe drawingsywhichform a part Another object is to, provide" an appa ratus Of this specification and whreinlikeireference whereimslurry is circulated with considerable characters in theseveral figures'designate similar? velocity in the lower portion of a tank without elements. disturbingan overlying relatively quiescentslurry Figure 1 is a vertical cross-sectionalview of: blanket. oneembodiment of'th invention;

Another object is toprovidean apparatus of Figure 2 is.a sectional view'takenalong line" this general type whereinthe floor of the tank. -4 f Figure is ccntinuouslyswept. free of-dep'osit; Figure3 is a vertical cross-sectional view'of." Other objects of the invention will become ap-A. another embodiment: of the invention which is. parentupon considerationof the description and .30particu1ar1y suitable for large tan s; theclaims which follow. Figure 4 is a partial verticalcross-sectional In slurry type liquid treating apparatus. the View O a modified'detail, and! liquidto betreated it usually is introduced into Figure 5 18a vertical cross-sectional view of a centrally located mixing-rand reaction zone a simplifiedsembodiment'of theiinventi'onr' where it is mixed withfreagentin the presence 5 The tank In, Shown in"1 igi1re1, may 'be' of of atslurry comprising solids separated from any suitable material, such as steel, and hasa previously. treated liquidv andretained and ac- Substa tial y fiat t om ll andian up t d ng cumulated inliquid undergoing treatment. The boundary Wall .12. 'Ifreated water. overflows. over mixture is discharged from the mixing and rea weir l3 into..a launder Hand is withdrawn action zone. into a pool of. slurry in the surround- 40 through aneflluent conduit IS. A depression or ing portionof the tank. An output. portion of sludg sump l6v is located centrallyinlthebottom.

liquid rises upwardly through the slurry pool H, and a sludgeblowofi" conduitxll leads from. leaving behind in the suspended slurry blanket, the sump. 16 to outside the tank H3. as it is sometimes called; solid" particles'formed A partition structure" 20. is centrally. arrangedf in the reactions between thex liquid'and' the V in the tank. and comprises'an outer tube 2|"and. chemicals. The major portion of" the mixture an innertube 22 which maybe sup'portedfro'm returns to the mixing and reactionzone to be the "outer tube as by brackets23. Thelo'wer mixed with further portions of liquid entering edges of both tubes are spacedabovethebottom" for treatment. of the tanki The upper-end of the outer-tub'e" In this slurry type treatment it is important-eo is at an'elevation above the overflow 'edgeof' the that the liqud discharged linto the slurry pool Weir l3, and the. upper edgel'of the inner tube be.uniformly distributedzt overthe rentire" 'cross' is belowsaid overflow edget: The'cha'nneliformediw'. sectionalcarea siofithe 130015120 provide'vforruniforma u. between the: outer? andiinneni tubes": is rclosed't'atli slurry :blanket susnensiom. It liS also: of: :impor. the :bottom ;by- ,a floor 24. s:

tancethat the =fioor:of-the-ta-nk beikeptfree. of-.55 Hollow fliquiddistribution: sarms oimconduitsw 25 extend from the outer tube radially across the tank in. Preferably four equally spaced arms 25 are provided, each registering with a port 2% in the tube 2 i. The liquid may be discharged from the arms 25 through one continuous slot, but preferably a plurality of downwardly opening discharge orifices 21 are provided along the lower part of the arms, as shown. The orifices 27 may be in the form of round holes or ngitudinal slots, and are suitably sized and spaced to provide for a substantially uniform distribution of liquid over the areas served. The outer ends of the arms can be supported from the upper part of the outer tube by any suitable means, such as by braces, or by cables 23, as shown. The arms may be supported in horizontal position, but with a fiat tank bottom it is preferred that they be inclined downwardly from the inner to the outer end, as shown, to provide for an inwardly increasing area below the arms for the return flow.

Baffle plates 30 are mounted on arms 25 and extend downwardly therefrom on each side, as best shown in Figure 2. Preferably these baffle plates decrease in vertical width from their inner to their outer ends, as shown in Figure 1, so that their lower edges are parallel to, or equidistant from, the bottom ll of the tank it.

A plate is mounted between the lower end of the inner tube 22 and the sump Hi. The plate 35 can be mounted in any suitable manner and. may be stationary. For purposes of illustration, the plate 35 is shown supported by a bracket 35 which may extend across the sump it. The plate 35 carries a guide bearing 31 wherein one end of a shaft 38 is journaled, the other end being fixed to a spider 39 mounted on the inner tube 22. This construction centers the partition structure 2i! and prevents its tilting during rotation, and the plate 35 shelters the sump is from any turbulence set up by the return flow of slurry to the inner tube 22. The whole assembly of inner tube 22, outer tube 2|, and arms 25 is rotatably supported by any suitable means. As shown in Figure 1 these means may take the form of a channel Ml surrounding the upper end of the outer tube 2i and riding on rollers til journaled in suitable bearings 42 which are supported from a beam or walkway 43 spanning the tank iii. A plurality of guide rollers 4'4 are journaled in bearings 45 which are also supported from the beam 63 and prevent side slipping of the channel at on its travel over the rollers 45. The partition structure is rotated by any suitable means, such as an internal ring gear 45 meshing with a. pinion A! which is mounted on the shaft of a speed reducer 48. The speed reducer is driven by any suitable motor 49, and the motor and reducer can be mounted on the beam 43.

Axially aligned within the partition structure 2% and at an elevation just above the upper edge of the inner tube 22 is a rotor 5a]. The rotor is preferably of the radial flow type and comprises a horizontal plate 51 and a plurality of vertical blades 52 afiixed to the lower side of the plate. Such a rotor affords excellent mixing and is capable of pumping considerable quantities of liquidat very low heads. The rotor is mounted on a shaft 53, which is driven by a motor-reducer 54, which can be mounted on the beam 43. Also supported by the beam 43 are e-liquid inlet conduit 55 and a reagent inlet 1ine'55. The liquid and reagent inlets preferably discharge, as shown, into the upper portion of the outer tube 2| adjacent the rotor 50. It is important that the liquid to be treated be mixed with the reagents in the presence of slurry. This affords an opportunity for the solid products of reaction formed in the treatment to deposit on previously formed slurry. particles. Thus, there is no deposition upon the surfaces of the tubes 21 and 22 nor upon the insides of the arms 25. Since the rotor, in the arrangement of the inlets shown in the drawings, handles only returned slurry which is non-depositing, the rotor does not become encrusted.

The structure described provides a mixing and reaction chamber or zone within the partition structure 20, a path for a circulation from the mixing and reaction chamber through the arms 25 across the tank and through the portion of the tank underlying the arms 25 back to the mixing and reaction chamber, a relatively quiescent zone above the rotating arms 25 wherein the slurry blanket is suspended, and, overlying the slurry interface, a clarified liquid zone in the upper portion of the tank.

The operation of the apparatus will be readily understood. Liquid to be treated, entering through inlet conduit 55, and any reagent, entering through line 5%, are mixed with slurry pumped upwardly through the inner tube 22 by rotation of the rotor 58. The downward flow of the mixture through the annular space or flow channel between the tubes 22 and 2! affords retention time for the reactions between liquid and reagent to be completed. The mixture enters the rotating arms 25 through ports 26 and is discharged under low head derived from the rotor '50 through the orifices 21 into the lower part of the slurry pool over laterally successive portions of the tank bottom as the arms 25 are rotated thereover. The orifices 2'! are sized and spaced to obtain a substantially uniform distribution of the discharged liquid over the cross sectional area of the outer tank portion. Slurry issuing from the orifices 21 is confined to the area underlying the rotating arms by the baffles iii The baffles 30 are just sufl'lciently spaced from the floor of the tank to provide an escapement for a through-put portion of liquid, which rises into the slurry blanket, displacing a like quantity of clear liquid from the slurry through the interface into the overlying clear water space from where it is withdrawn. The balance of the slurry discharged from the arms 25, which is usually a multiple of the throughput, is directed radially inwardly by the baiiles 30 and returns through the open lower end of the inner tube 22 into the mixing and reaction chamber. On its return passage the liquid sweeps the floor of the tank with considerable velocity, but the turbulence of the inward flow is confined by the baflles, and thus does not cause any substantial disturbance of the overlying slurry blanket. The arms, therefore, can be rotated at a much higher speed than would be permissible without the baiiies. One advantage of rotating the arms 25 at a relatively high speed is the more uniform distribution of the discharged slurry over the entire crosssectional area of the outer tank which provides a more uniform suspension of the slurry blanket. Further, deposits on the bottom of the tank are either resuspended in this relatively high velocity flow, or, if too heavy for resuspension, are swept across the floor toward the center of the tank, where they can deposit in the sump it. Thus,

the heaviest particles, which cannot beheld .in 1

suspension by the circulation in the tank, are removed, from the process, and lighter particles areretained-Ior. further. inI-the. process. i.

In .the embodiment growth andware. reused.

of the. invention shown -in-v Figures the innentube. 2zasis stationary, and

onlyithe outertube-Zl andthe arms25 rotate. In this embodiment thetank-l I a isv shown for i purposes of exemplification :as a concrete tank.

with a bottom- I Iawhich slopesinwardly toward an: annular-sump l6a.-

center portion .l of. the. l floorl i la, which 1 is-isur- Sludge is removed from. theesumpJBa-by sludgelpickup lines .18 awhich arel-connecteduto asludge outlet. pipe H. The

suitableimaterial, .such as steel, has a flat bottomrounded by the sump; l Ba -supports columns or-- brackets .60- which form a support. for theinner. endof a walkway 011-31 abridge fil-L- The innertube. 22a is affixed .to and. supported. umns th. Theouter. tube: ported. .from the. bridge 6| by the col- 2 I is rotatablyisupe and. is driven by a H moton-reducer-49-48 in .thesame manner as described in connection with Figure 1. I

The innerrtube has an outwardly extending lower. portion: 62 and. a cylindrical lower. ring or it The floor 24m oftheiouter tube 2 I. has

an .upstanding collarlfi l, aslshown. The collars .i

631 and 64 are slightlyspacedtfrom. eachother,

and a sealingicurtain fifitofeflexible material, such asrubberor the like, is aflixed to the upper collar 63" and hangs freely down over a portion of :the lower collarv to prevent any. substantial escape of l liquid through the small. gapbetween the .two collars. Theucoluinnsnfillextend through .slots provided inl the. outwardly extending portion 52 of .the inner tube 2211 In thistembodimentithe arms can extend horizontally, as the slopingbottomwi la afiords an 1 inwardly. increasingarea forlthe return flow. As

in the embodiment of Figure 1 bafiies an. extend.

downwardly. -from .the.arms125. and decrease in width. vertically fromtheir-inner to. their outer ends'so. that. their lower edges are para-llelto thesloping bottom of thetankr.

The operation of this embodiment. of: the vention isthesame asmdescribed in connection with Figure 1, except .thatthe inner tube remains stationary. while the outertube. 0 and arms i are rotated. This form of. the .apparatus is particu.-.

larly suited for large. tanks where a central support for. the walkway. is span.

provided to reduce its.

Figure 4 shows a modification ofthe outer tube which treatment. contains.large..quantities of heavy solids.

In. this embodiment. the: outer tube 2 lb is ex tended downwardly below the floor. 24b.- to adjacent the: tank-bottom, the lower edge .of the tube. being atstheelevation oi-the lower edges of the baiiie,p]atcs.30.- tube. 2112 forms a skirt. ID opentop ofnthesump Nb and the lower open end of theinnertube 223- The space within the skirt may be desirable where the liquid. under The lower. portion of the l which surrounds rthe.

m and below thefioorlZ lb-and theilowerend of tube 22 .forms a receiving. chamber ll into which thelpassageways below the rotating: arms 25 and between the baffleplates n dischargethe return. ing. slurry through isuitablel ports. in the skirt [0; escapement from.thepassageways, gap between the tanklbottoml and.

Theonly other is the narrow thelower edges ofthebafiles 36 andthe skirt 10. The area of the receiving. chamber 1| shouldbe larger thanthe combined area ofthe passageways. so .that thecvelocity .of :the slurry. entering the decreases,,permittinglsolidseflushed.

chamber] I.

from the liottomnf ;.tl1e ,tank..byltlie..high..velocity;

fio'w through thepassagewaysto depositinto the...

underlyingasump'; I61; Theareturnr flow in this positively. confined anddirected intor-ithe receiving chamber, and'the bottom of embodiment is the tank very eificiently washed.

The embodiment P of the invention shown in Figure 5 is simplified in several: respects and is treatment of a liquidsolidsparticularly suitable for containing relatively small. quantities of of somewhat light character. 1

The tank -.I0c of Figure 5 which maybe of any Hc andan upwardly expanding wall I210. The entire walll2c maybe of inverted frusto-conical form, or, as shown, only the lower portion of the wall is in inverted frusto-conical form, and the upper portion is i cylindrical. Obviously, instead of making -thelower part. of wall He in inverted frusto-conical shape v the wall may be cylindrical throughoutiand the desiredslope obtained by a in the art; The slurry cirly decreasingavelocity which is when dealing withlight solids as the flow to andith-roughtheslurry blanket must bequite low to prevent disturbance of the blanket and entrainment of light solids .by' the rising liquid. The arms25c inthisembodiment can be horizontal-and paralleltothebottom of thettank, i and the baffles 30 can be dispensed with, as it is notvnecessary, when dealing-with small-quantities of slurry, inwardly through a solidseoutlet conduit l'lc. v Obviously; theplate cansalsobe omitted in thisembodiment. Thei -partition"structure 2001 Figure 5 is the sameaslshown in Figure '1' and is centered and:v

rotatably? supported and driven in similar manner. The operation of i this embodiment i is the same as described "in.- connection with the other figures.

It-will beobvious to those-skilledin the artthat the: structures described and shown herein i can be modifiedein some. respects without departing from the-spirit and.scope ofthe'invention. Accordingly, .it is i tow-be. understood that the structuralidetails shown and: described herein are to be takenuas illustrations but not as limitations of the inventiom I olaimz 1..A .slurry type-liquid treating apparatus comprising.. a tank having a substantially flat overflow from an upper poi-tion oiisaidtank, means for with bottomrand an upstanding wall, an

drawingsolids-Efrem a lower portion of :said tank, a mixing andreaction-chamber having. a floor tan-ki and a wall said chambeninletmeans for liquid tobe treated and. for: any reagent used: in the: treatment: dischargingintolsaid mixing and-reaction chamber.

said. floor having. can: iapertured central r portion afiordingncommunication between the lower part of said vtank and sai d mixing andreaction chain wall of said mix-u ing and reaction chamber-.and-extending outber, .-a hollow armv sealed to :the

wardlytherefrom acrossethe lowermost portion of said tank, the spacezwlthinsaid arm being in hydraulim communicationnWith said mixing and reaction; chamber,-.- saidmarin having-means for dischargingdiquid downwardlvltherefrom, means. l

to provide: for a sharply confined sand. expanding return flow 'passageway. Solids" are withdrawndirectly from the slurry axially aligned in tank, i saidmixing and reaction chamber spacedabove"the:v bOttOm'IOf the risingzfrom said floor, a rotor in for driving said rotor, and means for rotating said arm over said tank bottom, whereby successive portions of said tank bottom are flushed by the discharge from said arm.

2. A slurry type liquid treating apparatus comprising a tank having a substantially flat bottom and an upstanding wall, means for withdrawing solids from a lower portion of said tank, a treated liquid outlet from an upper portion of said tank, a partition structure rotatably mounted in said tank and forming therein a central mixing and reaction chamber having a floor spaced above the bottom of said tank and a boundary wall extending to adjacent the top of the tank, wall means within said mixing and reaction chamber forming therein an upflow section and a downfiow section, a passageway from the lower portion of said tank through said floor into said upflow section, conduits aflixed to, and in hydraulic communication with, said downfiow section and extending outwardly therefrom across the lowermost portion of said tank, each conduit having a plurality of downwardly discharging orifices, a rotor in said mixing and reaction chamber affecting an inward flow across said bottom to said passageway to continuously flush said bottom, and to affect an upward flow through said passageway and upflow section, liquid inlet means discharging into said mixing and reaction chamber, means for introducing any reagents. into said mixing and reaction chamber and means for rotating said rotor and said partition structure.

3. A slurry type liquid treating apparatus comprising a tank having a bottom and a boundary wall, partition means in said tank forming therein a central mixing and reaction chamber spaced above the bottom of said tank, inlet means for liquid to be treated and any reagent discharging into said mixing and reaction chamber, an outlet for treated liquid from an upper portion of said tank, a solids outlet from a lower portion of said tank, a passageway from the lower portion of said tank into said mixing and reaction chamber, a tubular wall in said mixing and reaction chamber forming therein an upflow section and a downflow section, communicating with each other at the upper end of said wall, a rotor in said mixing and reaction chamber positioned to cause an upward flow from the lower part of the tank through said passageway into and through said upflow section, and means for rotating said rotor, characterized by means rotatably supporting said mixing and reaction chamber, motor driven means for rotating said mixing and reaction chamber, a floor in said downflow section, a plurality of conduits extending from a lower part of said mixing and reaction chamber across said tank, said conduits being in hydraulic communication with said mixing and reaction chamber, each conduit having a plurality of downwardly discharging orifices spaced along its lower portion, and a baflie plate afiixed to each side, said bafile plates extending downwardlyfrom said conduit to adjacent the bottom of the tank, and a sump centrallyv located in said bottom, said solids outlet leading from said sump, said baflle plates confining the discharge from said conduits and directing it across the tank bottom toward said passageway, to flush said bottom radially inwardly and over said sump.

4. A slurry type liquid treating apparatus comprising a tank having a bottom and an upstandingwall, an overflow from'an upper portion of said tank'a sump in a central part of 'said'botrtom, an outlet from said sump, a mixing and reaction chamber centrally mounted in said tank,

said mixing and reaction chamber having a floor portion spaced above the bottom of the tank and a tubular wall surrounding said floor portion and extending upwardly to an elevation above said overflow, means for rotatably supporting said mixing and reaction chamber in said tank, a tube within said mixing and reaction chamber and forming with said tubular wall a flow channel, an overflow from the space within said tube into said flow channel, a passageway from the lower portion of said tank into said tube, a rotor within said mixing and reaction chamber and arranged to pump slurry through said passageway and upwardly through said tube, a liquid inlet discharging within said mixing and reaction chamber, means for introducing reagent into said mixing and reaction chamber, a plurality of hollow arms aihxed to said tubular wall and in hydraulic communication with said flow channel, means for discharging liquid downwardly from said arms over the bottom area of said tank, baffle plates attached to each arm, one on each side thereof, each plate extending downwardly from its arm to adjacent the tank bottom and with its lower edge parallel to the tank bottom, and means for rotating said rotor and said mixing and reaction chamber.

5. The apparatus of claim 4, wherein said tubulaiwall extends also downwardly from said floor portion to adjacent the bottom of said tank.

6. The apparatus of claim 4 wherein the bottom of said tank is substantially flat, said arms are inclined downwardly from their inner to their outer ends, and the vertical extension of said baiile plates decreases from their inner to their outer ends.

'1. The apparatus of claim 4 wherein the bottom of said tank slants toward the center, said arms are horizontally mounted, and the vertical extension of said baffle plates decreases from their inner to their outer ends.

8. A slurry type liquid treating apparatus comprising a tank having a bottom and a boundary wall, outlet means for liquid to be treated determining the normal liquid level in said tank, means for Withdrawing solids from a lower portion of said tank, a partition structure rotatably supported in the center portion of said tank in spaced relationship to said bottom and comprising an open ended inner tube, an outer tube, and a floor portion between the lower edges of said tubes, said outer tube extending to an elevation above the normal liquid level in said tank and said inner tube terminating below said normal liquid level, inlet means for liquid to be treated and for reagent discharging within an upper portion of said partition structure, flow distributing conduits connected to, extending radially outwardly from, and in hydraulic communication with, the lower portion of said outer tube, each conduit having downwardly discharging orifices along its lower portion and a pair of bafile plates, one on each side, said baiile plates extending downwardly to adjacent the bottom of said tank and forming a confined flow area underneath said conduits, a rotor within said partition structure, said rotor being positioned to cause a circulation of liquid upwardly through said inner tube, downwardly between said outer and inner tubes, into said flow distributing conduits, out through said orifices and back through said confined area to the lower end of said inner tube, means for rotating said rotor, and means for rotating said partition structure.

from saidfloor f9 9. A slurry type liquid treating apparatus comprising a tank having a bottom and an upstanding wall, an overflow from an upper portion of said tank, means, for withdrawing solids from a lower portion of said tank, amixing and reaction chamber centrally mountedin said tank and having an annular floor portion spaced above the bottom offthe tank anda tubular wall extending portion toan elevation above said overflow, means for rotatably supporting said mixing and reaction chamber in said tank, a staing and reaction chambenmeans for introducing reagent into said mixing and reaction chamber, a plurality of hollow arms afiixedto a lower ,portion of said tubular wall and in hydraulic communication with said flow channel, said arms having downwardly discharging orifices, baille plates attached to said arms and extending downwardly from said arms to adjacent the tank bottom, and means for rotating said rotor and said mixing and reaction chamber.

10. A slurry type liquid treating apparatus comprising a tank having an outlet adjacent its top, a rotatably supported mixing chamber axially aligned in said tank, said mixing chamber having a boundary wall with a bottom edge terminating adjacent the bottom of said tank, and an annular floor portion at an elevation spaced above said bottom edge and forming a receiving chamber thereunder, a tube axially mounted in said mixing chamber and in hydraulic communication with said receiving chamber and extending to an upper level of said mixing chamber, a conduit opening into the mixing chamber above said floor portion and extending radially in the lower portion of said tank, plates depending from the sides of said conduit with their lower edges terminating adjacent the bottom of said tank to form a passageway underneath said conduit, the said passageway opening into said receiving chamber at its inner end, said conduit having an orifice discharging into said passageway, motor driven means positioned to circulate slurry inwardly through said passageway and through said receiving chamber to said mixing chamber, upwardly therein through said tube and then downwardly to and outwardly through said conduit in an amount in excess of the flow of liquid to be treated, a sump underlying said receiving chamber and open thereto, means for removing solids from said sump, inlet means for liquid to be treated and any reagent therefor discharging into the upper part of said mixing chamber, an annular slurry suspension chamber between the outer wall of the tank and the central mixing chamber, through which treated liquid rises to said outlet, and motor means for rotating said mixing chamber and said motor driven means.

11. In a slurry type liquid treatment apparatus of the type described, a tank having an outlet adjacent its top, wall means forming an outer annular chamber within said tank wherein treated liquid separates from a slurry suspension and rises toward said outlet, and a central mixing chamber adapted to receive incoming liquid to be -returned.- slurry,-

"910 treated, reagentiorthe treatment thereof and centrally located slurry return inlet means, around which the said mixing chamber is iformecha conduit radially extending from 1 said mixing chamber adjacent to but spaced from the bottom'of said tank, said conduit havin downwardly discharging distributing openings, a centrally placed sump and a discharge conduit from said sump, said sump being spacedbeneath the saidmixingchamber and slurry return inlet I means, meansfor-rotatably supporting said mix- ,ing. ,chamberand said conduit, motor means for rotating saidmixing chamber and said conduit,

,and slurry through said slurryrinlet means into and through said mixing chamber and said conduitin amountesubstantially in excess of the flow of motorr driven means adapted to circulate liquid-to be treated.

12. A slurry type liquid treating apparatus comprising a tankhaving afiat bottom and an inclined wall forming in said tank a rising space of upwardly increasing. cross-sectional area, a liquid outlet from'the upper portion of said tank,

means for withdrawing solids from a lower portion of said tank, a mixing and reaction chamber axially aligned in said tank and having a floor spaced above said bottom and a boundary wall extending upwardly from said floor, rotatable supporting means for said mixing and reaction chamber, a tube centrally aligned in said mixing and reaction chamber and in hydraulic communication with the lower portion of said tank through said floor, the upper end of said tube being at a lower elevation than the upper end of said boundary wall, a distribution conduit extending from a. lower portion of said boundary wall across a lower portion of said tank and in hydraulic communication with said mixing and reaction chamber, said conduit having downwardly discharging orifices, means for introducing liquid to be treated and reagent into said mixing and reaction chamber, a rotor in said mixing and reaction chamber constructed and positioned to cause a flow of slurry discharged from said conduit across the bottom of said tank into and through said tube, in excess of the flow of slurry to be treated, and motor means for rotating said mixing and reaction chamber and said rotor.

13. A slurry type liquid treating apparatus comprising a tank having a substantially flat bottom and an upstanding wall, treated liquid outlet means from an upper portion of said tank, means for withdrawing solids from a lower portion of said tank, a partition axially aligned and rotatably supported in said tank and extending in spaced relationship to said bottom from the lowermost portion of said tank to an elevation above said treated liquid outlet means, inlet means for liquid to be treated and reagent discharging into the space within said partition, a plurality of conduit ai'fixed to the lower end of said partition and in hydraulic communication with the space enclosed thereby, and having downwardly discharging orifice means, said conduits extending horizontally from said partition to adjacent said upstanding wall sufiiciently close to the tank bottom that the liquid discharged from said orifice means flushes said tank bottom, a floor in said partition having a central apertured portion, a second partition surrounding said apertured portion and extending from said floor upwardly within said first partition, an overflow from the space within said second partition to the space between said second and first partitions, a rotor mounted within said first partition and having a pumping capacity in excess of the quantity of newly incoming liquid to be treated and effecting upon its rotation a flow of liquid discharged from said orifice means inwardly across said tank bottom and upwardly through said apertured portion and the space within said second partition, and means for rotating said first partition and said rotor.

14. In a slurry type liquid treatment apparatus of the type described, a tank having a substantially flat bottom and an upstanding wall and having an overflow adjacent it top and means for withdrawing solids from a lower portion thereof, wall means forming an outer annular chamber within said tank wherein treated liquid separates from a slurry suspension and rises toward said outlet, and a central mixing chamber adapted to receive incoming liquid to be treated, reagent for the treatment thereof and returned slurry, said mixing chamber having a floor spaced above the bottom of the tank, centrally located slurry return inlet means in said floor, a conduit radially extending from said mixing chamber adjacent to but spaced from .12 the bottom of said tank, said conduit having downwardly discharging distributing openings, inlet means for liquid to be treated and for any reagent used in the treatment discharging into said mixing and reaction chamber, means for rotatably supporting said mixing chamber and said conduit, motor means for rotating said mixing chamber and said conduit, and motor driven means adapted to circulate slurry through said slurry inlet means into and through said mixing chamber and said conduit in amount substantially in excess of the flow of liquid to be treated.

WALTER J. HUGHES.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,245,587 Hughes June 1'7, 1941 2,348,123 Green et a1 May 2, 1944 2,355,069 Green Aug. 8, 1944 2,391,738 Prager Dec. 25, 1945 2,422,258 Prager June 17, 1947 2,425,371 Green Aug. 12, 1947 2,580,761 Green Jan. 1, 1952 

1. A SLURRY TYPE LIQUID TREATING APPARATUS COMPRISING A TANK HAVING A SUBSTANTIALLY FLAT BOTTOM AND AN UPSTANDING WALL, AN OVERFLOW FROM AN UPPER PORTION OF SAID TANK, MEANS FOR WITHDRAWING SOLIDS FROM A LOWER PORTION OF SAID TANK A MIXING AND REACTION CHAMBER AXIALLY ALIGNED IN SAID TANK, SAID MIXING AND REACTION CHAMBER HAVING A FLOOR SPACED ABOVE THE BOTTOM OF THE TANK AND A WALL RISING FROM SAID FLOOR, A ROTOR IN SAID CHAMBER, INLET MEANS FOR LIQUID TO BE TREATED AND FOR ANY REAGENT USED IN THE TREATMENT DISCHARGING INTO SAID MIXING AND REACTION CHAMBER, SAID FLOOR HAVING AN APERTURED CENTRAL PORTION AFFORDING COMMUNICATION BETWEEN THE LOWER PART OF SAID TANK AND SAID MIXING AND REACTION CHAMBER, A HOLLOW ARM SEALED TO THE WALL OF SAID MIXING AND REACTION CHAMBER AND EXTENDING OUT- 